POS0949 CLINICAL FACTORS ASSOCIATED WITH PNEUMOCYSTIS PNEUMONIA DESPITE ITS PRIMARY PROPHYLAXIS: A CASE-CONTROL STUDY
Authors: J. Y. Kim, J. I. Jung, E. B. Lee, J. W. Park
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Previous studies have suggested that primary prophylaxis against pneumocystis pneumonia (PCP) using trimethoprim-sulfamethoxazole (TMP-SMX) is beneficial in patients with rheumatologic diseases receiving immunosuppressive drugs<sup>[1]</sup>. However, there is little evidence for an optimal prophylaxis duration or a time point of prophylaxis withdrawal. <h3>Objectives</h3> This study aims to investigate the risk factors that are associated with PCP occurrence despite its primary prophylaxis, and, ultimately, to provide evidence regarding the ideal schedule for primary PCP prophylaxis. <h3>Methods</h3> This case-control study included treatment episodes of patients with rheumatic diseases who received prophylactic TMP-SMX with immunosuppressive treatment between 2010 and 2022 in a tertiary referral center in South Korea. The index date was defined as the date of starting the prophylactic dose of TMP-SMX. We captured PCP cases that occurred within 1 year from the index date based on the review of the medical record by two independent expert investigators. The effect of clinical factors, such as demographics, underlying disease, immunosuppressive treatment, and pattern of prophylaxis on the PCP occurrence was examined using binary logistic regression. <h3>Results</h3> A total of 1,379 treatment episodes were analyzed, and eleven cases of PCP occurred during the observation—a one-year PCP incidence of 0.80 (95% CI=0.40-1.43) per 100 person-years. In 10 cases (90.9%), PCP occurred after discontinuation of TMP-SMX prophylaxis, with a mean (SD) interval of 185.6 (90.9) days. The mean (SD) duration of prophylaxis in the PCP group was 108.5 (132.3) days. The main reasons for prophylaxis withdrawal in the PCP group were adverse events (5 cases) and treating physicians' decisions (5 cases). The dose of glucocorticoid at the time of prophylaxis cessation was the most critical risk factor for PCP. Patients who were receiving glucocorticoid more than 15 mg/day of prednisone equivalent at the time of TMP-SMX discontinuation showed a significantly higher odds of developing PCP (OR=15.06; 95% CI=1.92-117.94). The prophylaxis duration and presence of structural lung disease were not associated with PCP. This result was consistent in the multivariable analysis adjusted for age, underlying disease, rituximab treatment, azotemia, and lymphopenia (adjusted OR=12.21; 95% CI=1.52-98.24) (Table 1). <h3>Conclusion</h3> Discontinuation of TMP-SMX during glucocorticoid treatment greater than 15 mg of prednisone equivalent significantly increases the risk of PCP, which suggests that a time when glucocorticoids are tapered to less than 15mg/day of prednisone dosage equivalent may be a reasonable time to consider withdrawing PCP prophylaxis. <h3>Reference</h3> [1]Park JW, Curtis JR, Moon J, Song YW, Kim S, Lee EB. Prophylactic effect of trimethoprim-sulfamethoxazole for pneumocystis pneumonia in patients with rheumatic diseases exposed to prolonged high-dose glucocorticoids. Ann Rheum Dis. 2018;77(5):644-9. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.